Planet Guide and Information - Pluto

Distance from Sun (average)
5900 million km
2280 km
Length of day
6 days 9 hours
Length of year
248 years
Mean surface temperature

Pluto was discovered in 1930 and was awarded the position of the 9th planet in the solar system. However, in 2006 it was re-classified as a dwarf planet, as a result of the discovery of at least one larger Kuiper Belt object. The orbit of the planet around the Sun - taking nearly 250 years - is quite eccentric. At times this eccentricity brings it closer to the sun than Neptune. Pluto has three moons, the largest named Charon (pronounced KA-ron) is over half the diameter of Pluto. The otheres are named Nix and Hydra and are much smaller. All three can be seen in this HST image.